Download Speciation and Biodiversity

Speciation and Biodiversity
What is a Species?
• A species is a group of organisms that can
reproduce with each other to produce fertile
descendants.
• But be careful because there are are animals
that are not species because they cannot
reproduce.
Background
• Adaptation – Accumulation of advantageous
traits within the members of a population,
enabling them to survive variations in the
environment
• Can be structural (affecting organs),
physiological (affecting functioning of the
organism), or behavioral (changes in behavior)
Speciation
• Speciation is an evolutionary process
• It describes the mechanism that creates new
species from previous ones
• There are four types:
Allopatric
Peripatric
Parapatric
Sympatric
Allopatric Speciation
• Barrier Forms
• Isolation Occurs
• Variance in environmental pressures results in
adaptation
• Mutation occurs, resulting in different species
Allopatric Speciation
Peripatric Speciation
• Like allopatric speciation, but there is a
variation in population sizes
• Occurs at the margin of the ancestral species’
range rather than with a barrier formation
• Isolation leads to daughter species
• Ancestral species does not become extinct
Peripatric Speciation
Parapatric Speciation
• Parapatric speciation occurs when a niche is
formed
• But unlike allopatric and peripatric speciation
there is a small overlap between the
populations
• As a result, this type of speciation is
characterized by a gradient in which end
species cannot interbreed, but interior species
can
Parapatric Speciation
Sympatric Speciation
• Sympatric speciation occurs within the same
geographical zone
• Divergence occurs even as the range
completely overlaps
• Originally a controversial concept as there was
a lack of evidence (most examples could be
characterized as micro-allopatric)
• But a few examples have been observed
Sympatric Speciation
Biodiversity
• Biodiversity – The quantity and variety of
organisms that are living on earth or have
lived on earth in the past
• The result of evolution
and adaptation
• Therefore biodiversity is
the result of speciation
• It is a resource to protect